It goes into effect tomorrow, as the park’s 2008 season officially opens.

Sullivan County residents will now be allowed to book a seven-month stay at the lakeside park. The rate: $250 per month — but you have to agree to stay for the whole season, which runs through October. You’ll have to pay the first three months up-front, and the balance will be due at the beginning of July.

To get the special rate and extended-stay booking, you must have a physical Sullivan County address. In other words, P.O. boxes will not suffice.

The new plan involves only “up to 100” of the park’s nearly 200 rentable campsites. Reservations are “first come, first served.” It was approved Friday by the Sullivan County Commission’s Observation Knob Park Committee.

It marks a partial about-face in county policy.

Up until a couple of years ago, Sullivan County had allowed campers to stay at “Ob Knob” indefinitely — many were from out-of-state and had over time built permanent structures at their leased campsites. Some had been on the same site for years.

In an effort to make the park’s campsites more accessible to county residents, the county evicted all the long-term campers and last season put in place a two-week limit on campsite rentals.

Under the plan approved by the committee Friday, lakefront campsites will not be available for season-long rentals — they’ll still be under the two-week maximum rule, at $125 per week.

The county’s budget for this fiscal year includes about $205,000 for operation of the park, with most of the money — more than $132,000 — projected to come from camping rentals and other fees at the park.

The balance of the operating costs, about $72,000, were budgeted to come from the park’s fund balance. As of Friday afternoon, revenue generated by camping and other fees at the park totaled $43,241, according to information provided by the county’s accounting department.

The season-long rental plan could generate as much as $175,000 to help cover the park’s operating costs, County Mayor Steve Godsey said, possibly freeing up other revenues to pay for improved amenities and facilities.

Godsey said higher fuel prices are one reason he supports offering the season-long rentals to county residents. He said the cost of buying gas to haul a camper to and from the park could keep some county residents from making repeat trips to Observation Knob Park under the current “two weeks in, two weeks out” policy.

County Commissioner Randy Morrell said higher gas prices might prove to be a boon for business at the park, as people seek vacation spots closer to home.

Committee members said the offer for season-long rentals might be expanded next year to include non-county residents — if response from county residents this year fails to book all 100 slots set aside for the program. On the flip side, they said the number of season-long slots could be reduced — or completely eliminated in future years — if temporary campsite use picks up.

Those who book season-long stays this season will not automatically be guaranteed the same spot — or any spot at all — for next year. The county will not be offering off-season “storage” rates, Park Superintendent Dan Helton said.